1. Field Of The Invention
The present invention relates to apparatus for accurately positioning and transporting multiple immunochemical, diagnostic or serological test devices and, more particularly, to such apparatus which facilitates automated processing of the test devices.
The art of analytical chemistry has been greatly advanced since biochemistry began emerging as a primary scientific frontier, requiring increasingly sophisticated analytical methods and tools to solve problems. Likewise the medical profession has lent impetus to the growth of analytical chemistry, with its desiderata of both high precision and speed in obtaining results.
To satisfy the needs of the medical profession as well as other expanding technologies, such as the brewing industry, chemical manufacturing, etc., a myriad of analytical procedures, compositions and apparatus have evolved, including the so called "dip-and-read" type reagent test devices. Reagent test devices enjoy wide use in many analytical applications, especially in the chemical analysis of biological fluids, because of their relatively low cost, ease of usability, and speed in obtaining results. In medicine, for example, numerous physiological functions can be monitored merely by dipping a reagent test device into a sample of body fluid, such as urine or blood, and observing a detectable response, such as a change in color or a change in the amount of light reflected from or absorbed by the test device.
Many of the "dip-and-read" test devices for detecting body fluid components are capable of making quantitative or at least semiquantitative measurements. Thus, by measuring the response after a predetermined time, an analyst can obtain not only a positive indication of the presence of a particular constituent in a test sample, but also an estimate of how much of the constitutent is present. Such test devices provide the physician with a facile diagnostic tool as well as the ability to gage the extent of disease or of bodily malfunction.
Illustrative of such test devices currently in use are products available from the Ames Division of Miles Laboratories, Inc. under the trademarks CLINISTIX, MULTISTIX, KETOSTIX, N-MULTISTIX, DIASTIX, DEXTROSTIX, and others. Immunochemical, diagnostic or serological test devices such as these usually comprise one or more carrier matrices, such as absorbent paper, having incorporated therein a particular reagent or reactant system which manifests a detectable response, e.g., a color change in the presence of a specific test sample component or constituent. Depending on the reactant system incorporated with a particular matrix, these test devices can detect the presence of glucose, ketone bodies, bilirubin, urobilinogen, occult blood, nitrite, and other substances. A specific change in the intensity of color observed within a specific time range after contacting the test device with a sample is indicative of the presence of a particular constituent and/or its concentration in the sample. Some of these test devices and their reagent systems are set forth in U.S. Pat. Nos. 3,123,443; 3,212,855; 3,814,668; etc.
Regardless of whether the test device is used for the determination of biological fluid or the analysis of a commercial or industrial fluid, the normal procedure requires that each test device separately come in contact with the sample or specimen to be tested and then that the test device be visually or instrumentally analyzed. Means has been sought in the art for accurately positioning and retaining multiple individual test devices for automated processing. Prior to the present invention no known system had the capability of achieving the desiderata mentioned above in which multiple, individual test devices could be retained in apparatus for automatic processing without a change in format of the test device.
2. Description Of The Prior Art
The traditional dip-and-read test device can be manufactured at relatively low cost and it is convenient for an individual to use, but it is not well suited for use with highly automated equipment. For automated equipment to be of any advantage, it must result in a benefit with respect to cost, handling, and/or speed of obtaining information. Apparatus currently available for instrumentally reading individual reagent strips, such as the SERALYZER reflectance photometer or the CLINITEK reflectance photometer, manufactured and sold by the Ames Division of Miles Laboratories, Inc., Elkhart, Ind., requires that each reagent test device must be manually loaded into the instrument after contacting the test device with specimen or sample to be tested. Manual loading requires that the reagent test device be properly positioned in the instrument within a limited period of time after contacting the solution or substance to be tested. At the end of the analysis, each test device must be removed from the instrument for disposal.
A different format is presently used in the CLINILAB automated urinalysis system, which is manufactured and sold by the Ames Division of Miles Laboratores, Inc., Elkhart, Ind. The CLINILAB instrument uses a cassette containing reagent areas mounted seriatim on a continuous plastic substrate which is wound into a reel and housed in a cassette. While the CLINILAB reagent cassette is well suited for automation, the manufacturing cost for this type of format amounts to eight times that of the conventional dip-and-read test device format mentioned above.
In accordance with the present invention instrumental testing for immunochemical, diagnostic or serological purposes can be achieved using multiple conventional dip-and-read type reagent test devices. The apparatus results in an efficient, economical, rapid and convenient way of performing such analyses.